1. Field of the Invention
The present invention relates to a directional screen that displays an optical image projected from a projector such as a liquid crystal projector and an image projection system that displays an image by using the screen.
2. Description of the Related Art
An image projection system such as a projection device that projects an optical image by using a high-intensity CRT, a liquid crystal projector, or the like to display an image has been widely used as a tool for communicating information to multiple users because the system can simply display a high-definition image on a large screen. There have been proposed ideas for the screen for a projector such as an improvement in efficiency for light utilization through the coverage of the surface of the screen with a white material or light reflective film having a high light reflectance and an improvement in visibility for multiple observers through light diffusion caused by the spreading of beads on the surface. In addition, as disclosed in, for example, JP 2002-169224 A, a screen surface is provided with a directional reflection structure such as a lenticular lens so that an image is efficiently displayed to multiple observers.
Although a conventional screen having directivity can efficiently converge the light of the projected image from the projector on an observer owing to its directivity, an influence of external light such as illumination light greatly contributes to the-brightness of the surface of the screen. Accordingly, the screen has a problem in that it is difficult to display a clear image in a bright room.